It began with her ferocity on the high school basketball court. As co-captain her senior year, Sarah Palin was a point guard who made the final free throw that won the Wasilla Warriors their first state championship.

A decade later, the nickname resurfaced when she was a 28-year-old political novice on the Wasilla City Council. She turned on a veteran council member who had coaxed her to run for office, blocking a bill that would have steered business to his garbage-hauling firm.

The moniker was revived once again in 2003, when Alaska's governor, whom she would later unseat, appointed her to a state oil-and-gas commission. As a brand-new member, she challenged the ethics of the panel's leader, the chairman of state's Republican Party, forcing him ultimately to resign.

Since long before she became Alaska's youngest -- and first female -- governor 20 months ago, Sarah Louise Heath Palin has been making her mark as an unlikely upstart. Yesterday, she did it again, accepting Sen. John McCain's surprise offer to be his running mate.

Palin, a 44-year-old mother of five who hunts caribou and was once a beauty queen, rose to the statehouse by challenging the corruption that has become endemic in Alaska, even if it meant taking on the Republican establishment there, including the former governor and the state's congressional delegation.

Although her résumé does not fit the mold of most vice presidential nominees, her acts of dissidence appear to have endeared her to McCain, who regards himself as an independent-minded Republican. Her evangelical Christian faith -- she believes in creationism and is adamantly opposed to abortion -- may help him court skeptical social conservatives. And the fact that her eldest son joined the Army and is leaving soon for Iraq reinforces McCain's own military heroism.

Her swift ascent to the governorship, and now to a vice presidential nomination, is regarded by some in Alaska as a case of fortunate timing, for someone who possesses the right outsider's tactics at the right political moment. Others cite driving ambition and instinctive opportunism -- a willingness to turn on political patrons to get ahead.

One of her central gubernatorial campaign pledges -- to clean up the state's government -- has been called into question by critics because of an investigation into whether the state public safety commissioner was fired because he refused requests to dismiss a state trooper who had been married to her younger sister.

Although her name had been murmured as a possible long-shot running mate, it was only last month that she told an interviewer on CNBC: "As for that VP talk all the time, I tell you, I still can't answer that question until someone answers for me what is it exactly that the VP does every day."

Even her press secretary sounded startled by the choice. "The chattering had been out there," Bill McAllister said in an interview yesterday morning. "But I had no sense of momentum to it."

Born in Idaho, Palin became an Alaskan as an infant when her parents, Chuck and Sally Heath, hauled their young family and their belongings up the Alaskan Highway in search of adventure. They settled eventually in Wasilla, about 45 miles north of Anchorage. Palin's official biography describes it as a place with a "reputation for junky yards and cranky land-owners who didn't mind using the serious end of a shotgun to run off trespassers." Ivan Moore, a veteran political pollster in Anchorage, described Wasilla as "the most fearsomely conservative region of the state."

Her father was a science teacher and her mother became a school secretary. The family would go on camping trips to hunt moose, bear and sometimes wild sheep, according to Adele Morgan, a friend since childhood. Palin is a lifetime member of the National Rifle Association, and even today, as governor, she fishes for salmon in Bristol Bay.

The third of four children, Palin was shaped by her father's love of sports and her mother's Christian faith, according to Kaylene Johnson, a journalist whose biography of the governor was published this year. Palin's father was her track coach, and she played on the softball team, but her real passion was basketball. "She doesn't like sitting on the sidelines," Johnson said.

Her mother, meanwhile, made sure that Sundays were for church.

Palin entered the Miss Wasilla beauty pageant and won, playing the flute for her talent. She went on to compete for Miss Alaska and was a runner up.

She began to date Todd Palin, a part Yup'ik Eskimo who grew up in the bush of a native Alaskan village, when he transferred to Wasilla's high school to play basketball. She went off to college, studying first in Hawaii before transferring to the University of Idaho, where she majored in journalism with a minor in political science.

Not long after she returned to Wasilla, she and Todd Palin eloped at the local courthouse -- 20 years ago yesterday -- recruiting two strangers from across the street to serve as witnesses.

A commercial fisherman and champion snowmobile racer, Todd Palin has worked as an oilfield worker for BP on Alaska's North Slope. He now works for a union.

Their first child, Track, was born in 1989. Their youngest, Trig, was born just four months ago; consistent with her opposition to abortion, she continued the pregnancy after learning early on that her baby had Down syndrome.

As a child, Palin showed little political consciousness, Johnson said, but she devoured newspapers and news magazines from an uncommonly early age.

She worked as a television sportscaster and weather reporter and was 28 when she set her sights on the Wasilla City Council. A social conservative in tune with the town, Palin easily won a seat, and the issues tended to revolve around garbage collection and the local police force. Along the way, she made an enemy of her political patron. She then ousted the three-term incumbent Republican mayor, winning by 211 votes, according to her biography.

In 2002, Palin narrowly lost a bid for lieutenant governor, running as a supporter of then-Gov. Frank Murkowski. Her reward was an appointment to the powerful Oil and Gas Conservation Commission, which regulates the state's energy industries. Within months of assuming the $115,000-a-year job, Palin castigated her fellow commissioner, Randy Ruedrich, then the chairman of the state Republican Party, saying he was conducting political business on state time. She sparked an investigation that led to his resignation and a $12,000 fine.

"Randy Reudrich served as the very powerful, king-making, top-dog chairman of the Republican Party of Alaska," Moore said. "This was what forged her reputation."

In 2006, Palin went after Murkowski, defeating the governor in a GOP primary before winning in November. The election put into the governor's mansion a pro-life executive who is opposed to stem cell research, favors the teaching of creationism in public schools and is a longtime advocate of hunters' rights.

But as governor, Palin has played down her social views. Instead, she has focused on the powerful oil industry, helping to impose higher taxes on its soaring profits and pushing to construct a massive new natural gas pipeline.

"She's conservative in ideology, but she's very practical," said lobbyist Paul Fuhs, who battled Palin over the gas line and eventually reached a compromise. "What you see is what you get. She's very upfront."

One of Palin's first official acts as governor was to sell on eBay a gubernatorial jet that Murkowski had bought.

But she has angered two of Alaska's leading Republicans -- Sen. Ted Stevens and Rep. Don Young -- by refusing to support their decades-long practice of securing federal money for the state, including Young's effort to obtain $233 million for a structure dubbed the "Bridge to Nowhere" by critics because it would have connected a small town with an island populated with 50 people. In her short time in state office, she has repeatedly thwarted Stevens's and Young's interests and, at times, challenged their candidates -- including their children.

So far, her popularity among her constituents is untarnished. In the most recent state survey, four out of five Alaskans said they support her, according to Moore. How that will translate nationally is not yet clear.

For now, even her friends, staffers and Alaska's most careful political observers are a bit startled by her leap onto the Republican presidential ticket. "I feel like I'm in the twilight zone," Moore said, "to think that in this short period of time she's on the national stage."